Drawworks systems and methods

ABSTRACT

A drawworks system for a mineral extraction system includes a drum mounted on a drum shaft and configured to support a cable. The system also includes a gearbox assembly having a gearbox housing, a gearbox supported by the gearbox housing and having a gearbox input shaft and a gearbox output shaft, wherein the gearbox input shaft is configured to be coupled to at least one motor and the gearbox output shaft is coupled to the drum shaft to drive rotation of the drum shaft and the drum, and a brake supported by the gearbox housing and coupled to the drum shaft to block rotation of the drum shaft and the drum, wherein the gearbox and the brake are positioned on one side of the drum along an axial axis of the drawworks system.

BACKGROUND

This section is intended to introduce the reader to various aspects ofart that may be related to various aspects of the present disclosure,which are described and/or claimed below. This discussion is believed tobe helpful in providing the reader with background information tofacilitate a better understanding of the various aspects of the presentdisclosure. Accordingly, it should be understood that these statementsare to be read in this light, and not as admissions of prior art.

Natural resources, such as oil and gas, are used as fuel to powervehicles, heat homes, and generate electricity, in addition to variousother uses. Once a desired resource is discovered below the surface ofthe earth, drilling and production systems are often employed to accessand extract the resource. These systems may be located onshore oroffshore depending on the location of the desired resource. Further,such systems may include a wide variety of components, such as variouscasings, fluid conduits, tools, and the like, that facilitate extractionof the resource from a well during drilling or extraction operations. Insome systems, a drawworks system (e.g., hoisting or lifting assembly) isprovided to raise and/or to lower certain components relative to thewell. However, some drawworks systems may be large and/or complex.Furthermore, some drawworks systems may be difficult to maintain and/orrepair, thereby resulting in increased downtime during certainmaintenance and/or repair operations, and/or resulting in inefficientdrilling operations.

BRIEF DESCRIPTION OF THE DRAWINGS

Various features, aspects, and advantages of the present disclosure willbecome better understood when the following detailed description is readwith reference to the accompanying figures in which like charactersrepresent like parts throughout the figures, wherein:

FIG. 1 is a schematic diagram of a portion of a drilling and productionsystem, in accordance with an embodiment of the present disclosure;

FIG. 2 is a perspective front view of a drawworks system that may beused in the drilling and production system of FIG. 1, in accordance withan embodiment of the present disclosure;

FIG. 3 is a top view of the drawworks system of FIG. 2;

FIG. 4 is a cross-sectional side view of the drawworks system of FIG. 2,taken within lines 4-4 shown in FIG. 3;

FIG. 5 is a cross-sectional side view of the drawworks system of FIG. 2,taken within lines 5-5 shown in FIG. 3;

FIG. 6 is a perspective rear view of the drawworks system of FIG. 2;

FIG. 7 is a left side view of the drawworks system of FIG. 2;

FIG. 8 is a right side view of the drawworks system of FIG. 2;

FIG. 9 is a front view of the drawworks system of FIG. 2;

FIG. 10 is a graph illustrating hook load across block speed, inaccordance with an embodiment of the present disclosure;

FIG. 11 is a schematic diagram of an embodiment of a control system thatmay be used in the drilling and production system of FIG. 1;

FIG. 12 is a flow diagram of a method of operating a drawworks system,in accordance with an embodiment of the present disclosure;

FIG. 13 is a perspective view of an embodiment of a motor assembly thatmay be used in the drawworks system of FIG. 2;

FIG. 14 is a side of the motor assembly of FIG. 13;

FIG. 15 is a perspective view an embodiment of an adapter that may beused within the motor assembly of FIG. 13;

FIG. 16 is a schematic diagram of an embodiment of a planetary gearsetthat may be used within the motor assembly of FIG. 13;

FIG. 17 is a cross-sectional side view of an embodiment of atransmission that may be used within the motor assembly of FIG. 13,wherein an annular sleeve of the transmission is in an extendedposition;

FIG. 18 is a cross-sectional side view of the transmission of FIG. 17,wherein the annular sleeve of the transmission is in a retractedposition;

FIG. 19 is a cross-sectional side view of the transmission of FIG. 17,wherein the annular sleeve of the transmission is in an intermediateposition;

FIG. 20 is a perspective view of an embodiment of the annular sleevethat may be used within the transmission of FIG. 17;

FIG. 21 is a perspective view of an embodiment of a lubricant passagewaythat may be used within a drive shaft of the transmission of FIG. 17;and

FIG. 22 is a cross-sectional side view of an embodiment of a portion ofa motor assembly that may be used in the drawworks system of FIG. 2.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

One or more specific embodiments of the present disclosure will bedescribed below. These described embodiments are only exemplary of thepresent disclosure. Additionally, in an effort to provide a concisedescription of these exemplary embodiments, all features of an actualimplementation may not be described in the specification. It should beappreciated that in the development of any such actual implementation,as in any engineering or design project, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which may vary from one implementation toanother. Moreover, it should be appreciated that such a developmenteffort might be complex and time consuming, but would nevertheless be aroutine undertaking of design, fabrication, and manufacture for those ofordinary skill having the benefit of this disclosure.

The present embodiments are generally directed to drawworks systems andmethods (e.g., hoisting or lifting systems and methods) for use within adrilling and production system. Certain embodiments include a drawworkssystem having one or more motors, a gearbox, a brake, and a drum (e.g.,annular drum) mounted on a drum shaft. The drum is configured to supporta cable (e.g., wire) that is coupled to components of a hoisting systemfrom which drilling equipment, such as a drill string, is suspended.Rotation of the drum causes the cable to retract (e.g., wrap or windabout the drum) and/or to extend (e.g., unwrap or unwind from the drum)to raise and/or to lower the drilling equipment relative to a drillfloor. For example, rotation of the drum in a first direction may causethe cable to extend to lower the drill string to facilitate drilling awellbore through subterranean formations. In certain embodiments, thedrum shaft may be coupled to an output shaft of the gearbox, and the oneor more motors may be coupled to an input shaft of the gearbox to enablethe one or more motors to drive rotation of the drum.

As discussed in more detail below, in certain embodiments, both thegearbox and the brake are supported by a gearbox housing and/or arepositioned on one side of the drum (e.g., on the same side of the drumalong an axial axis of the drawworks system). In certain embodiments,the drum shaft, the output shaft of the gearbox, and the brake arealigned and share a common rotational axis (e.g., coaxial). In certainembodiments, the drum shaft extends through the gearbox and to thebrake, which is directly coupled to the drum shaft to enable the braketo block rotation of the drum.

Additionally or alternatively, in certain embodiments, each of the oneor more motors may include or be coupled to a respective transmission.For example, in some embodiments, the drawworks system may include atleast two motors, each coupled to a respective multi-speed transmission.As discussed in more detail below, such a configuration may enable thedrawworks system to efficiently lift a load when using both motors andto also lift the load at a reduced speed using only a single motor(e.g., after failure of the other motor). The disclosed embodiments mayenable reduced downtime (e.g., after failure of the other motor) and/orefficient drilling operations, for example. The disclosed embodimentsmay also provide a compact drawworks system and/or may facilitatemaintenance and/or repair of the components of the drawworks system.

With the foregoing in mind, FIG. 1 is a schematic diagram of a portionof a drilling and production system 10, in accordance with an embodimentof the present disclosure. As shown, the system 10 includes a mast 12positioned on a drill floor 14 and a hoisting system 16 configured toraise and to lower drilling equipment relative to the drill floor 14. Inthe illustrated embodiment, the hoisting system 16 includes a crownblock 18, a traveling block 20, and a drawworks system 22. As shown, acable 24 (e.g., wire) extends from the drawworks system 22 and couplesthe crown block 18 to the traveling block 20. In the illustratedembodiment, a top drive 26 is coupled to the traveling block 20, and adrill string 28 is suspended from the top drive 26 and extends throughthe drill floor 14 into a wellbore 30. The top drive 26 may beconfigured to rotate the drill string 28, and the hoisting system 16 maybe configured to raise and to lower the top drive 26 and the drillstring 28 relative to the drill floor 14 to facilitate drilling of thewellbore 30.

Any suitable number of lines of the cable 24 may extend between thecrown block 18 and the traveling block 20, and the cable 24 may have anysuitable diameter, such as a diameter in a range of 1 to 7 centimeters(cm) or a diameter between approximately 3 to 5, 4 to 4.75, or 4.25 to4.5 cm. While FIG. 1 illustrates a land-based drilling and productionsystem 10 to facilitate discussion, it should be understood that thedisclosed embodiments may be adapted for use within an offshore drillingand production system. Furthermore, it should be understood that thedisclosed drawworks system 22 may be utilized in any of a variety ofdrilling and production systems.

FIG. 2 is a perspective front view of the drawworks system 22 that maybe used in the drilling and production system 10 of FIG. 1. Tofacilitate discussion, the drawworks system 22 and its components may bedescribed with reference to an axial axis or direction 40, a lateralaxis or direction 42 (or a radial axis or direction), and acircumferential axis or direction 44. In the illustrated embodiment, thedrawworks system 22 includes a skid 46 (e.g., frame or supportstructure) that supports a drum assembly 48, a gearbox assembly 50, anda motor assembly 52.

In certain embodiments, the drum assembly 48 may include a drum 54(e.g., annular drum) mounted on a drum shaft and positioned within adrum housing 55. As shown, an outer surface 57 (e.g., annular surface)of the drum 54 includes grooves 59 (e.g., circumferentially-extendinggrooves or Lebus grooves) that are configured to support a cable (e.g.,the cable 24) that is wrapped circumferentially about the drum 54. Insome embodiments, the drum 54 may have a diameter in a range of 90 to150 centimeters (cm). In some embodiments, the drum 54 may have adiameter of between approximately 110 and 130, 115 and 125, or 118 and120 cm.

In certain embodiments, the gearbox assembly 50 may include a gearbox 56(e.g., dual input, parallel shaft, reduction gearbox, triple reduction,single speed, and/or single helical gearbox) and a brake 58 (e.g.,pneumatic multi-disc brake or plate brake) supported within and/orcoupled to (e.g., directly coupled via one or more fasteners) a gearboxhousing 60 (e.g., frame or support structure supported by, coupled to,and/or in contact with the skid 46). Such a configuration may enable thegearbox housing 60 to transfer reaction torque from the brake 58 and/oroutput torque from the gearbox 56 to the skid 46, thereby providing acompact structure (e.g., the gearbox assembly 50 having the gearbox 56and the brake 58 coupled to the gearbox housing 60) that effectivelytransfers forces to the skid 46. For example, the gearbox housing 60 maysurround or cover the gearbox 56 (e.g., the shafts and gears of thegearbox 56), and the brake 58 may directly contact and may be directlycoupled to the gearbox housing 60, such as via one or more fasteners. Asdiscussed in more detail below, an output shaft of the gearbox 56 may bedirectly coupled (e.g., via splines) to the drum shaft to drive rotationof the drum shaft and the drum 54, and the brake 58 may be directlycoupled (e.g., via splines) to the drum shaft to block rotation of thedrum shaft and the drum 54.

In certain embodiments, the brake 58 may be configured to hold ahoisting load of the drawworks system 22. As discussed in more detailbelow, the brake 58 may be a fail-safe brake (e.g., spring applied andair released) that is biased toward a braked position and may be held ina non-braked position via an air supply. In certain embodiments, thebrake 58 may be utilized for emergency or parking braking operations(e.g., only for emergency or parking braking operations, non-cyclicalbraking operations, or holding a suspended load), and the drawworkssystem 22 is configured to utilize regenerative braking for regularcyclical service braking during hoisting operations.

In certain embodiments, the motor assembly 52 may include one or moreelectric motors 62 (e.g., alternating current [AC] motors or directcurrent [DC] motors) supported within respective motor housings 66 andrespective transmissions 64 (e.g., multi-speed planetary transmissions)supported within respective transmission housings 65. Each transmission64 may be generally configured to adjust the power output of therespective motor 62. The illustrated embodiment includes two motors 62;however, it should be understood that any suitable number (e.g., 1, 2,3, 4, or more) of motors 62 and/or respective transmissions 64 may beprovided. As discussed in more detail below, respective drive shaftsextending from the one or more motors 62 of the motor assembly 52 may becoupled (e.g., via crowned gear couplings) to an input shaft (e.g.,double sided pinion shaft) of the gearbox 56.

In certain embodiments, each of the motors 62 may be configured tooperate continuously at least equal to or greater than approximately1150 horsepower (HP), and each of the motors 62 may be configured tooperate intermittently at least equal to or greater than approximately1500 HP (e.g., during hoisting operations or over a limited period oftime, such as less than 10, 20, 30, 60, 90, 120, 180, or 300 minutes).Thus, during hoisting operations, the two motors 62 shown in FIG. 2 maytogether provide a total of at least equal to or greater thanapproximately 3000 HP. In some embodiments, each of the motors 62 may beconfigured to operate continuously between approximately 800-1800,1000-1500, or 1100-1200 HP and/or intermittently between approximately1200-2000, 1400-1800, or 1500-1600 HP. In certain embodiments, each ofthe respective transmissions 64 may be a two (a more) speed transmission(e.g., having a gear with a 1:1 gear ratio, a gear with a 2:1 gearratio, and a neutral gear), and the respective transmissions 64 mayenable the drawworks system 22 to hoist the load at a reduced speedusing less than all of the motors 62 (e.g., upon failure of one of thetwo motors 62 shown in FIG. 2). For example, during normal operation ofthe drawworks system 22, each the respective transmissions 64 may be setto a 1:1 gear ratio and both of the motors 62 may drive rotation of thedrum 54 via the gearbox 56 to move a load at a first speed. However,upon certain circumstances (e.g., if a first motor 62 fails), therespective transmission 64 coupled to the first motor 62 may be shiftedto the neutral gear, and the respective transmission 64 coupled to asecond motor 62 (e.g., intact motor) may be shifted to a 2:1 gear ratioto enable the drawworks system 22 to lift the load at approximately halfof the first speed using only the second motor 62. The neutral gear mayalso enable the other motor (e.g., the second motor 62) to operate witha 1:1 gear ratio with reduced inertia (e.g., system inertia), therebyproviding faster acceleration and/or deceleration in low loadcircumstances, for example.

As discussed in more detail below, in certain embodiments, the drawworkssystem 22 may include or be coupled to a control system (e.g., anelectronic control system having an electronic controller having aprocessor and a memory) that is configured to receive and to processdata from various sensors (e.g., a temperature sensor coupled to thebrake 58, a speed sensor coupled to the motor 62, a speed sensor coupledto the drum shaft, a position or gear ratio sensor within thetransmission 64, etc.) positioned about the drawworks system 22, toreceive control signals and/or operator inputs, to provide an indication(e.g., a visual indication via a display and/or an audible indicationvia a speaker) of a condition of the drawworks system 22 (e.g., failureof the motor 62) to an operator, and/or to control components of thedrawworks system 22 (e.g., move the brake 58 between the braked positionand the non-braked position, shift gears of the transmissions 64, etc.)based on the data and/or the operator inputs, for example. In certainembodiments, the drawworks system 22 disclosed herein may utilizegaseous fluid (e.g., air or inert gas, such as nitrogen) in operation(e.g., to cool the motors 62, to operate the brake 58, etc.), and maynot utilize liquid fluid (e.g., water) in operation.

FIG. 3 is a top view of the drawworks system 22. As shown, the drumassembly 48 includes the drum 54 positioned within the drum housing 55,and the drum 54 is mounted on a drum shaft 70 (e.g., non-rotatablymounted so as to rotate with the drum shaft 70) that extends in theaxial direction 40 between the drum 54 and the gearbox 56 of the gearboxassembly 50. In the illustrated embodiment, the gearbox 56 and the brake58 are supported by the gearbox housing 60 and are positioned on oneside (e.g., the same side) of the drum 54 along the axial axis 40.

In the illustrated embodiment, the motor assembly 52 includes two motors62 coupled to respective transmissions 64. As shown, each motor 62 issupported within a respective motor housing 66 and its respectivetransmission 64 is supported within a respective transmission housing65. In certain embodiments, the motor assembly 52 (e.g., the one or moremotors 62 and respective transmissions 64) may be positioned at adifferent location along the lateral axis 42 than the drum 54, the drumshaft 70, and/or the brake 58 (e.g., the motor assembly 52 may beseparated from the drum 54, the drum shaft 70, and/or the brake 58 alongthe lateral axis 42). For example, in the illustrated embodiment, bothmotors 62 and their respective transmissions 64 are positioned rearward(e.g., along the lateral axis 42) of each of the drum 54, the drum shaft70, and the brake 58. In the illustrated embodiment, one motor 62 ispositioned on one side of the gearbox 56 and another motor 62 ispositioned on another side (e.g., an opposite side) of the gearbox 56along the axial axis 40.

In some embodiments, a rotational axis 72 of the drum 54 and the drumshaft 70 and a rotational axis 74 of drive shafts 76 (e.g., outputshafts) of the motor assembly 52 may be generally parallel to oneanother and separated from one another along the lateral axis 42. Incertain embodiments, the rotational axis 72 of the drum 54 and the drumshaft 70 is also the rotational axis of an output shaft 86 of thegearbox 56 and/or the brake 58. In the illustrated embodiment, thegearbox 56 extends along the lateral axis 42 to couple the motorassembly 52 to the drum assembly 48. In particular and as discussed inmore detail below, an input shaft 100 of the gearbox 56 is positioned ata first location along the lateral axis 42 and is coupled to the driveshafts 76 of the motor assembly 52, and the output shaft 86 of thegearbox 56 is positioned at a second location along the lateral axis 42and is coupled to the drum shaft 70. In certain embodiments, the inputshaft 100 of the gearbox 56 is parallel to the output shaft 86 of thegearbox 56 (e.g., a parallel shaft gearbox 56).

FIG. 4 is a cross-sectional side view of the drawworks system 22, takenthrough the drum shaft 70 and within lines 4-4 shown in FIG. 3. Asshown, the drum 54 is mounted (e.g., non-rotatably mounted via a splinedinterface 73, such as one or more male and female splines or matingteeth or grooves, so as to rotate with the drum shaft 70) to the drumshaft 70, which is rotatably supported above the skid 46 by bearings 80within bearing housings 82. For example, in the illustrated embodiment,the bearing housings 82 are coupled to respective brackets 84 (e.g.,frames) that are coupled to the skid 46.

In the illustrated embodiment, the drum shaft 70 is coupled to an outputshaft 86 (e.g., annular or hollow shaft) of the gearbox 56, such as viaa splined interface 88 (e.g., one or more male and female splines ormating teeth or grooves). Thus, rotation of the output shaft 86 drivesrotation of the drum shaft 70 and the drum 54. In the illustratedembodiment, the drum shaft 70 is directly coupled to the brake 58, suchas via a splined interface 90 between the drum shaft 70 and a hub 92(e.g., annular or hollow shaft) of the brake 58. Thus, blocking rotationof the hub 92 of the brake 58 blocks rotation of the drum shaft 70 andthe drum 54. As shown, the gearbox 56, the output shaft 86, and thebrake 58 are positioned on one side (e.g., the same side) of the drum 54along the axial axis 40, and the drum shaft 70 extends through theoutput shaft 86 of the gearbox 56 and into the hub 92 of the brake 58.Thus, the drum 54 is positioned on one side of the gearbox 56 and thebrake 58 is positioned on another side (e.g., opposite side) of thegearbox 56 along the axial axis 40 (e.g., the gearbox 56 is positionedbetween the drum 54 and the brake 58 along the axial axis 40). As shown,the drum shaft 70, the output shaft 86, and the hub 92 of the brake 58are aligned with one another and are configured to rotate about therotational axis 72 (e.g., coaxial). In the illustrated embodiment, afirst end 75 of the drum shaft 70 is supported by the respective bracket84, and a second end 77 of the drum shaft 70 is positioned within thehub 92 of the brake 58. However, in some embodiments, the second end 77of the drum shaft 70 may extend through the brake 58 and may bepositioned on a side of the brake 58 opposite the gearbox 56 and thedrum 54.

In some embodiments, the brake 58 may be a fail-safe brake that isbiased toward a braked position in which the brake 58 blocks rotationthe drum shaft 70 unless an air supply (e.g., via a pneumatic system) isprovided to overcome the biasing force to hold the brake 58 in anon-braked position. For example, in certain embodiments, the brake 58may include brake discs 83, biasing members 85, and radially-extendingdiscs 87 coupled to the hub 92. In operation, the air supply may beprovided to the brake 58 to overcome the biasing force of the biasingmembers 85 to separate the brake discs 83 from the radially-extendingdiscs 87, thereby enabling rotation of the hub 92 and the drum shaft 70.When the air supply is removed, the biasing members 85 may urge thebrake discs 83 into contact with the radially-extending discs 87,thereby blocking rotation of the hub 92 and the drum shaft 70. As notedabove, the brake 58 may be utilized for emergency or parking brakingoperations (e.g., non-cyclical braking operations or holding a suspendedload), and the drawworks system 22 is configured to utilize regenerativebraking for regular cyclical service braking during hoisting operations.Although splined interfaces 73, 88, 90 are shown, these interfaces mayhave any suitable configuration to couple the components to one another,such as a key-slot interface, bushings, or the like. It should beunderstood that the brake 58 may be any suitable type of brake,including but not limited to a hydraulically-controlled brake or aplate-type brake (e.g., having a radially-extending disc supported on ahub coupled to the drum shaft 70 and calipers configured to engage thedisc to block rotation of the drum shaft 70).

FIG. 5 is a cross-sectional side view of the drawworks system 22, takenthrough an input shaft 100 (e.g., double-sided pinion input shaft) ofthe gearbox 56 and within lines 5-5 shown in FIG. 3. As shown, the inputshaft 100 is coupled to respective drive shafts 76 of the motorassemblies 52 via respective gear couplings 102 (e.g., crowned gearcouplings). In the illustrated embodiment, the motor assembly 52includes two motors 62 within respective motor housings 66 and the twotransmissions 64 within respective transmission housings 65.

In certain embodiments, the transmissions 64 may be multi-speedtransmissions, such as a two-speed transmission configured to operatewith a first gear ratio (e.g., 1:1 gear ratio), a second gear ratio(e.g., 2:1 gear ratio), and in neutral. Although examples providedherein relate to a two-speed transmission that provides a 1:1: gearratio and a 2:1 gear ratio, it should be understood that the drawworkssystem 22 may include any of a variety of multi-speed transmissionsproviding any suitable number of gear ratios and/or any suitable gearratio. In the illustrated embodiment, each transmission 64 is positionedbetween its respective motor 62 and the input shaft 100 of the gearbox56 along the axial axis 40. As shown, each transmission housing 65 iscoupled to the motor housing 66 via an adapter 98 (e.g., annularadapter, spacer, or support structure) positioned between the motorhousing 66 and the transmission housing 65. As shown, the input shaft100 and the drive shafts 76 are aligned with one another and areconfigured to rotate about the rotational axis 74 (e.g., coaxial).

Additional features of the drawworks system 22 are shown in FIGS. 6-9.For example, FIG. 6 is a perspective rear view of the drawworks system22 and shows the skid 46, the drum housing 55 of the drum assembly 48,the gearbox housing 60 of the gearbox assembly 50, and the transmissionhousing 65 and the motor housing 66 of the motor assembly 52. FIG. 7 isa left side view of the drawworks system 22 and shows the skid 46, thedrum shaft 70, the drum 54, and the drum housing 55 of the drum assembly48. FIG. 7 also shows the gearbox housing 60 of the gearbox assembly 50and the motor housing 66 of the motor assembly 52. FIG. 8 is a rightside view of the drawworks system 22 and shows the skid 46, the brake 58within the gearbox housing 60 of the gearbox assembly 50, as well as themotor housing 66 of the motor assembly 52. FIG. 9 is a front view of thedrawworks system 22 and shows the skid 46, the drum 54 and the drumhousing 55 of the drum assembly 48, the gearbox housing 60 of thegearbox assembly 50, and the motor housing 66 of the motor assembly 52.

FIG. 10 is a graph 118 illustrating hook load 120 (e.g., load coupled tothe traveling block 20 or load supported by the hoisting system 16)across block speed 122 (e.g., speed of the traveling block 20), inaccordance with an embodiment of the present disclosure. As shown, insome embodiments, the drawworks system 22 may be configured to operatewith a first maximum block speed, such as approximately 6.4 feet/second(ft/sec) (i.e., approximately 1.95 meters/second [m/s]) or betweenapproximately 6 and 7 ft/sec (i.e., between approximately 1.8 and 2.2m/s), with the two motors 62 operating at a first speed, such as a totalof approximately 2300 revolutions per minute (RPM), and while each ofthe respective transmissions 64 are set to a first gear ratio (e.g., a1:1 gear ratio) (line 124). In certain embodiments, the drawworks system22 may be configured to operate at a second maximum speed, such asapproximately 8.4 ft/sec (i.e., approximately 2.6 m/s) or betweenapproximately 8 and 9 ft/sec (i.e., between approximately 2.4 and 2.8m/s), with the two motors 62 operating at a second speed, such as atotal of approximately 3000 RPM, and while the respective transmissions64 are set to the first gear ratio (e.g., a 1:1 gear ratio) (line 126).

As noted above, the drawworks system 22 may be configured to move thehook load 120 at a reduced speed (e.g., approximately half speed) and/orat a reduced hook load 120 (e.g., approximately half hook load) at fullspeed using only a single motor 62. For example, as shown in the graph118, the drawworks system 22 may be configured to operate at a thirdmaximum speed, such as between approximately 4 and 5 ft/sec (i.e.,between approximately 1.2 and 1.5 m/s), with a single motor 62 operatingat the second speed, such as 3000 RPM, and while the respectivetransmission 64 is set to a second gear ratio (e.g., a 2:1 gear ratio)(line 128). In some embodiments, the drawworks system 22 may beconfigured to operate at a fourth maximum speed, such as betweenapproximately 3 and 4 ft/sec (i.e., between approximately 0.9 and 1.2m/s), with a single motor 62 operating at the first speed, such as 2300RPM, and while the respective transmission 64 is set to the second gearratio (e.g., a 2:1 gear ratio) (line 130). Various features, such as thediameter of the drum 54, the type of motors 62, the number of lines ofthe cable 24, a size and/or weight of the cable 24, the type oftransmissions 64, the type of gearbox 56, and/or the arrangement andrelative positioning of the components of the drum assembly 48, thegearbox assembly 50, and the motor assembly 52 may enable the drawworkssystem 22 to operate with the parameters illustrated in the graph 118 ofFIG. 10. The disclosed configuration may enable the drawworks system 22to provide the illustrated relatively high block speeds at relativelylow motor speeds that enable efficient and adequate regenerative braking(e.g., using the motor assembly 52), thereby enabling the drawworkssystem 22 to raise and/or to lower the drilling equipment at therelatively high block speeds over a relatively greater distance orheight of the wellbore 30 when using multiple motors 62. The disclosedembodiments also enable the drawworks system 22 to raise and/or to lowera load (e.g., a full load or a rated maximum load) at a reduced speedwhen using only a single motor 62 (e.g., the full load or the ratedmaximum load at approximately half speed as compared to using two motors62). The disclosed embodiments may also result in reduced downtime(e.g., after failure of one motor 62) and/or efficient drillingoperations, and/or may provide a compact drawworks system and/or mayfacilitate maintenance and/or repair of the components of the drawworkssystem 22, for example.

FIG. 11 is a schematic diagram of an embodiment of a control system 134that may be utilized within the drilling and production system 10 ofFIG. 1. As shown, the control system 134 includes a controller 136(e.g., electronic controller) having a processor 138, a memory 140, anda user interface 142. The user interface 142 may be configured toreceive an operator input and/or to provide an indication, such as avisual indication on a display and/or an audible indication via aspeaker. The control system 134 may include one or more sensors, such asa sensor 144 configured to monitor a speed of a respective motor 62, asensor 145 configured to monitor a gear ratio of the transmission 64(e.g., by measuring a position of one or more components within thetransmission 64), a sensor 146 configured to monitor a speed of the drumshaft 70, a sensor 148 configured to monitor a temperature within thebrake 58, or the like. The sensors 144, 145, 146, 148 may providesignals indicative of a condition of the drawworks system 22 to theprocessor 138 to enable the processor 138 to provide an indication viathe user interface 142 and/or to control various components of thedrawworks system 22. For example, in some embodiments, the sensor 144may provide a signal that enables the processor 138 to determine thatthe motor 62 is not functioning properly (e.g., has failed). In certainembodiments, the processor 138 may provide an audible indication and/orinstruct a display to provide a visual indication of the condition ofthe drawworks system 22 to the operator, thereby enabling the operatorto take appropriate action, provide appropriate inputs, or the like. Incertain embodiments, upon determination of motor failure, the processor138 may automatically control a valve to adjust (e.g., remove) the airsupply that holds the brake 58 in the non-braked position, therebycausing the brake 58 to move to the braked position and to blockrotation of the drum shaft 70. Indeed, various steps and processesdisclosed herein with respect to the hoisting operations may beconducted via operator inputs and/or may be conducted automatically bythe processor 138 in response to the condition of the drawworks system22.

In the illustrated embodiment, the controller 136 includes the processor138 and the memory 140. The controller 136 may also include one or morestorage devices and/or other suitable components. The processor 138 maybe used to execute software, such as software for controlling thedrawworks system 22. Moreover, the processor 138 may include multiplemicroprocessors, one or more “general-purpose” microprocessors, one ormore special-purpose microprocessors, and/or one or more ApplicationSpecific Integrated Circuits (ASIC), or some combination thereof. Forexample, the processor 138 may include one or more Reduced InstructionSet (RISC) or Complex Instruction Set (CISC) processors. The memory 140may include a volatile memory, such as Random Access Memory (RAM),and/or a nonvolatile memory, such as Read Only Memory (ROM). The memory140 may store a variety of information and may be used for variouspurposes. For example, the memory 140 may store processor-executableinstructions (e.g., firmware or software) for the processor 138 toexecute, such as instructions for controlling the drawworks system 22,processing signals from the sensors 144, 145, 146, 148, and/or providingindications via the user interface 142. The storage device(s) (e.g.,nonvolatile storage) may include read-only memory (ROM), flash memory, ahard drive, or any other suitable optical, magnetic, or solid-statestorage medium, or a combination thereof. The storage device(s) maystore data (e.g., condition data, thresholds, or the like), instructions(e.g., software or firmware for controlling the drawworks system 22, orthe like), and any other suitable data. Although the control system 134is illustrated with one controller 136 to facilitate discussion, itshould be understood that the control system 134 may be a distributedcontrol system having multiple controllers 136 and may be configured tocarry out various other functions.

FIG. 12 is a flow diagram of an embodiment of a method 150 of operatingthe drawworks system 22. The method 150 includes various stepsrepresented by blocks. Although the flow diagram illustrates the stepsin a certain sequence, it should be understood that the steps may beperformed in any suitable order, certain steps may be carried outsimultaneously, and/or certain steps may be omitted, where appropriate.Certain steps of the method 150 may be performed by an operator viamanual operation of an actuator, via an input into a control system(e.g., an electronic control system having an electronic controllerhaving a processor and a memory device, such as the control system 134),or the like. Additionally or alternatively, certain steps of the method150 may be performed as an automated procedures (e.g., by an electroniccontrol system, such as the electronic control system 134).

With the foregoing in mind, the method 150 may begin by operating themotors 62 of the drawworks system 22 at a designated power and with therespective transmissions at a first gear ratio (e.g., 1:1 gear ratio) todrive rotation of the drum 54 via the gearbox 56 and to move a load at afirst speed, in step 152. In step 154, the brake 58 may be applied toblock rotation of the drum 54. As discussed above, in certainembodiments, an operator may provide an input (e.g., via the userinterface 142 of the controller 136) to control a pneumatic system toremove the air supply to enable the brake 58 to block rotation of thedrum 54. In some embodiments, the controller (e.g., the controller 136)may apply the brake 58 automatically in response to data received fromone or more sensors (e.g., sensors 144). In certain embodiments, thebrake 58 may be applied in response to an indication of a failed motor62 (e.g., failure of one motor 62 of the multiple motors 62) during ahoisting operation, for example.

In step 156, while the brake 58 is in the braked position and the drum54 is stationary, a first transmission 64 coupled to a first motor 62(e.g., a failed motor) may be switched to a neutral position. In step158, a second transmission 64 coupled to a second motor 62 (e.g., anintact motor) may be switched from the first gear ratio to a second gearratio (e.g., 2:1 gear ratio) to enable the drawworks system 22 to carrythe load at a reduced speed (e.g., at approximately half of the firstspeed) with the second motor 62. The transmission gear ratios may beadjusted via an operator input (e.g., via the user interface 142 of thecontroller 136) or automatically by the controller 136 in response tovarious signals, such as a signal from the sensor 146 that indicates thedrum shaft 70 is stationary and/or other signals that indicate the brake58 is adequately applied, for example.

In step 160, the brake 58 may be returned to the non-braked position(e.g., via control of the pneumatic system to provide the air supply viaan operator input or automatically via the controller 136) to enablerotation of the drum 154. In step 162, the second motor 62 that iscoupled to the second transmission 64 that is set at the second gearratio may be operated at the designated power to move the load (e.g., atapproximately half of the first speed). Such a configuration may reducedowntime, increase the efficiency of certain drilling operations (e.g.,by enabling completion of certain drilling operations), and/or mayenable delay of repair to the first motor 62 until a more convenienttime, for example.

It should be understood that the various components of the drawworkssystem 22 may have various configurations. For example, FIGS. 13-21illustrate an embodiment of a portion of the motor assembly 52 that maybe utilized within the drawworks system 22. In particular, FIG. 13 is aperspective view and FIG. 14 is a side view of an embodiment of aportion of the motor assembly 52 having one motor 62 positioned withinthe motor housing 66 and a respective transmission 64 positioned withinthe transmission housing 65. In the illustrated embodiment, the adapter98 is positioned between the motor housing 66 and the transmissionhousing 65 along the axial axis 40. As shown, the adapter 98 includes afirst flange 200 (e.g., annular flange) configured to be coupled to acorresponding flange 201 (e.g., annular flange) of the motor housing 66via one or more fasteners 202 (e.g., threaded fasteners, such as bolts)and a second flange 204 (e.g., annular flange) configured to be coupledto a corresponding flange 205 (e.g., annular flange) of the transmissionhousing 65 via one or more fasteners 206 (e.g., threaded fasteners, suchas bolts). The adapter 98 may include one or more axially-extendingportions 208 that extend axially between and couple the first flange 200and the second flange 204 to one another and one or more openings 210(e.g., vents) positioned axially between the first flange 200 and thesecond flange 204 and circumferentially between adjacentaxially-extending portions 208 to provide air flow about the motor 62and/or to vent exhaust from the motor 62, for example. As shown, thegear coupling 102 is provided to couple the drive shaft of the motorassembly 52 to another component, such as the input shaft of the gearbox56. As discussed in more detail below, the motor assembly 52 may includea fluid drive system 213 (e.g., actuator system) configured to controlone or more valves 214 (e.g., shift valves) to adjust a flow of fluid(e.g., pressurized liquid or gas) to adjust the gear ratio of thetransmission 64.

FIG. 15 is a perspective view of an embodiment of the adapter 98 coupledto the motor housing 66. As shown, a motor shaft 220 extends axiallythrough a central opening 222 of the adapter 98. In the illustratedembodiment, the adapter 98 includes the first flange 200, the secondflange 204, the one or more axially-extending portions 208, and the oneor more openings 210. The adapter 98 may enable the motor housing 66 andthe transmission housing 65 to be coupled to one another, therebyenabling adjustment of the power output of the motor 62 and providing acompact motor assembly 52 for use within the drawworks system 22.

As discussed above, in certain embodiments, the transmission 64 may be amulti-speed transmission (e.g., two-speed transmission configured tooperate with a 1:1 gear ratio, a 2:1 gear ratio, and in neutral). Such aconfiguration may enable the drawworks system 22 to hoist the load at areduced speed using less than all of the motors 62 (e.g., upon failureof one of the two motors 62 shown in FIG. 2). For example, during normaloperation of the drawworks system 22, each of the respectivetransmissions 64 may be set to a first gear ratio (e.g., a 1:1 gearratio) and both of the motors 62 may drive rotation of the drum 54 viathe gearbox 56 to move a load at a first speed. However, upon certaincircumstances (e.g., if a first motor 62 fails), the respectivetransmission 64 coupled to the first motor 62 may be shifted to theneutral gear, and the respective transmission 64 coupled to a secondmotor 62 (e.g., intact motor) may be shifted to a second gear ratio(e.g., a 2:1 gear ratio) to enable the drawworks system 22 to lift theload at a reduced speed (e.g., approximately half of the first speed)using only the second motor 62.

With the foregoing in mind, FIG. 16 is a schematic diagram of anembodiment of a gearset 230 (e.g., planetary gearset) that may beutilized within the transmission 64 of the motor assembly 52. In theillustrated embodiment, the gearset 230 is a five-planet epicyclicgearset with a sun gear 232, planet gears 234, and a ring gear 236. Insome embodiments, the gearset 230 may be configured to provide areduction ratio of greater than or equal to 2:1 (e.g., 2:1, 3:1, 4:1,5:1, 10:1, or the like).

FIG. 17 is a cross-sectional side view of a portion of the transmission64 that may be utilized in the motor assembly 52 of the drawworks system22. As shown, the transmission 64 is positioned within the transmissionhousing 65, which may be coupled to the motor housing 66 via the adapter98. The motor shaft 220 driven by the motor 62 extends from motorhousing 66, through the adapter 98, and into a cavity 221 at one end ofthe drive shaft 76. The motor shaft 220 is coupled to the sun gear 232(e.g., non-rotatably coupled to rotate with the sun gear 232), such asvia a splined interface 238 (e.g., one or more male and female splinesor mating teeth or grooves), and is coupled (e.g., rotatably coupled) tothe drive shaft 76 via bearings, such as a first bearing 240 (e.g.,cylindrical bearing) and/or a second bearing 242 (e.g., needle bearing).The gear coupling 102 is provided to couple the drive shaft 76 of themotor assembly 52 to another component, such as the input shaft of thegearbox 56.

As shown, the transmission 64 includes the gearset 230 having the sungear 232, the planet gears 234 supported by a planet gear carrier 244,and the ring gear 236. The transmission 64 includes a sleeve 250 (e.g.,annular shift sleeve, piston, or cylinder that may be driven by fluid)that circumferentially surrounds at least a portion of the drive shaft76. In the illustrated embodiment, a radially-inner surface 249 (e.g.,radially-inner wall, annular surface, internal splined surface) of thesleeve 250 is coupled (e.g., non-rotatably coupled via a splinedinterface 251) to the drive shaft 76 and is configured to move along theaxial axis 40 relative to the gearset 230, the transmission housing 65,and/or the drive shaft 76. When the sleeve 250 is in the illustratedfirst position 252 (e.g., extended position), a radially-outer surface247 (e.g., radially-outer wall, annular surface, external splinedsurface) of the sleeve 250 engages the sun gear 232 (e.g., non-rotatablyengages the sun gear 232 via a splined interface 254), and thus, thetransmission 64 provides the 1:1 gear ratio and the drive shaft 76rotates with the motor shaft 220.

As shown, the sleeve 250 includes a protrusion 253 (e.g., annularprotrusion or flange) that extends radially inward from the sleeve 250and which may support a seal 255 (e.g., annular seal) that seals againstan outer wall 257 (e.g., radially-outer wall or annular surface) of thedrive shaft 76. In the illustrated embodiment, a support sleeve 256(e.g., annular sleeve) is coupled (e.g., non-rotatably coupled, such asvia one or more fasteners or threaded interfaces) to the outer wall 257of the drive shaft 76 (e.g., the support sleeve 256 does not moverelative to the drive shaft 76). The support sleeve 256 may include aprotrusion 258 (e.g., annular protrusion or flange), which may support aseal 259 (e.g., annular seal) that seals against the inner wall 249 ofthe sleeve 250. While shown as a physically separate component in FIG.17, it should be understood that the support sleeve 256 may beintegrally formed with the drive shaft 76, in some embodiments. Asshown, a support ring 261 (e.g., annular ring) is coupled (e.g.,non-rotatably coupled, such as via one or more fasteners or threadedinterfaces) to the sleeve 50 and may support a seal 263 (e.g., annularseal) that seals against the support sleeve 256. In the illustratedembodiment, the support ring 261 is coupled to the sleeve 250 via afastener 265 (e.g., threaded fastener); however, it should be understoodthat the support ring 261 may be coupled to the sleeve 250 via anysuitable technique or may be integrally formed with the sleeve 250(e.g., one piece).

In the illustrated embodiment, an extension cavity 260 (e.g., annularcavity or sealed cavity) is defined between the inner wall 249 of thesleeve 250 and the outer wall 257 of the drive shaft 76 along the radialaxis 42. The protrusions 253, 258 and their respective seals 255, 259may also define and seal the extension cavity 260 and block fluid flowfrom the extension cavity 260. As shown, the extension cavity 260 isfluidly coupled to a first passageway 262 (e.g., extension passageway)that extends through the drive shaft 76 and through a rotary union 264that enables transfer of a fluid between components that rotate relativeto one another. It should be understood that the first passageway 262may be positioned in any suitable plane or location within the driveshaft 76 to provide fluid to the extension cavity 260. Indeed, whilecertain passageways and ports may be illustrated (e.g., in solid ordotted lines) in various locations to facilitate discussion, it shouldbe understood that any of the passageways and ports disclosed herein maybe positioned in any of a variety of planes or locations about thetransmission 64 to fluidly couple respective components (e.g., fluidsources and cavities) to one another. In the illustrated embodiment, therotary union 264 includes a first component 266 (e.g., annularcomponent) that is coupled to and/or fixed relative to the transmissionhousing 65 and a second component 268 (e.g., annular component) that iscoupled to the drive shaft 76 (e.g., non-rotatably coupled to the driveshaft 76 such that the second component 268 rotates with the drive shaft76 and relative to the first component 266). In operation, a respectiveshift valve 214 (e.g., an extension valve) may be controlled to adjust aflow of a fluid (e.g., pressurized pneumatic or hydraulic fluid) throughthe first passageway 262 to the extension cavity 260, thereby drivingthe sleeve 250 into the first position 252, as shown by arrow 269.

As shown, the transmission 64 includes a bearing 270 (e.g., ballbearing) to support the drive shaft 76 and/or to facilitate rotation ofthe drive shaft 76 relative to the transmission housing 65. In theillustrated embodiment, a seal carrier 246 (e.g., annular seal carrier)supporting one or more seals 248 (e.g., annular seals) may be providedto block a flow of fluid (e.g., lubricant, pressurized pneumatic orhydraulic fluid, or the like) from the rotary union 264 and/or thetransmission 64. The illustrated embodiment includes the sensor 145(e.g., inductive proximity switch, position sensor, gear ratio sensor,or the like) configured to monitor a position of the sleeve 250. Asshown, the sleeve 250 includes a radially-outwardly extending protrusion276 (e.g., annular protrusion) that may be detected by the sensor 145.In the illustrated embodiment, the sensor 145 is a proximity switch;however, it should be understood that the sensor 145 may be any suitabletype of sensor (e.g., optical, acoustic, magnetic, or the like) that isconfigured to detect the position of the sleeve 250 and to provide anoutput (e.g., a signal) indicative of the position of the sleeve 250.

FIG. 18 is a cross-sectional side view of a portion of the transmission64 with the sleeve 250 in a second position 290 (e.g., retractedposition). When the sleeve 250 is in the illustrated second position290, the radially-outer surface 247 of the sleeve 250 engages the ringgear 236 (e.g., non-rotatably engages the ring gear 236 via a splinedinterface 294, such as one or more male and female splines or matingteeth or grooves, to rotate the sleeve 250 with the ring gear 236), andthus, the transmission 64 provides a different gear ratio (e.g., a 2:1gear ratio) to adjust the power output by the motor 62.

In the illustrated embodiment, a retraction cavity 300 (e.g., annularcavity or sealed cavity) is defined between the inner wall 249 of thesleeve 250 and an outer wall 302 (e.g., radially-outer wall or annularsurface) of the support sleeve 256 along the radial axis 42. Theprotrusions 258, 261 and their respective seals 259, 263 may also defineand seal the retraction cavity 300 and block fluid flow from theretraction cavity 300. As shown, the retraction cavity 300 is fluidlycoupled to a second passageway 304 (e.g., retraction passageway) thatextends through the drive shaft 76 and through components 266, 268 ofthe rotary union 264. In operation, a respective shift valve 214 (e.g.,a retraction valve) may be controlled to adjust a flow of a fluid (e.g.,pressurized pneumatic or hydraulic fluid) through the second passageway304 to the retraction cavity 300, thereby driving the sleeve 250 intothe second position 290, as shown by arrow 308.

FIG. 19 is a cross-sectional side view of a portion of the transmission64 with the sleeve 250 in a third position 320 (e.g., intermediate orneutral position). In the third position 320, the sleeve 250 ispositioned between the first position 252 and the second position 290along the axial axis 40 and does not engage the gearset 230 (e.g., theradially-outer surface 247 of the sleeve 250 does not engage theplanetary gearset 230), and thus, the transmission 64 is in neutral,such that rotation of the motor shaft 220 is not transferred to thedrive shaft 76.

The transmission 64 may include various features to enable the sleeve250 to achieve and/or to maintain the intermediate position 320. Forexample, in the illustrated embodiment, the transmission 64 includes anadjustable stop 330 (e.g., annular stop or sleeve) that is configured tolimit and/or to block movement of the sleeve 250 along the axial axis40. As shown, a détente 332 (e.g., annular détente) is provided aboutthe radially-inner surface 249 of the sleeve 250 and is configured toengage a groove 334 (e.g., annular groove) in the radially-outer surface257 of the drive shaft 76. In some embodiments, the détente 332 mayinclude multiple spring loaded balls arranged circumferentially aboutthe radially-inner surface 249, although any suitable arrangement isenvisioned. Together, the adjustable stop 330 and the détente 332 maysupport the sleeve 250 in the intermediate position 320 withoutenergizing the shift valve 214 that provides the fluid to the retractionchamber 300. In the illustrated embodiment, a wear sleeve 336 (e.g.,annular wear sleeve or thrust bearing) is provided between theadjustable stop 330 and the sleeve 250 along the radial axis 42 tofacilitate relative axial movement between the adjustable stop 330 andthe sleeve 250.

In operation, to shift from the first position 252 to the intermediateposition 320, the respective shift valve 214 may be controlled toprovide fluid to the retraction chamber 300 via the second passageway304, thereby driving the sleeve 250 axially relative to the drive shaft76 in a first direction, as shown by arrow 308. At the same time, arespective shift valve 214, or other suitable valve, may be controlledto provide a flow of fluid through a stop passageway 338 to a stop space340 (e.g., annular space) to drive the stop 330 axially in a seconddirection, opposite the first direction, as shown by arrow 342. The stop330 may contact the sleeve 250 (e.g., the protrusion 276 of the sleeve250) to block the sleeve 250 from moving axially to the second position290 and may block the sleeve 250 from engaging the ring gear 236. Insome embodiments, the fluid pressure within the retraction cavity 300and/or the stop space 340 may be removed, and the sleeve 250 may remainin the intermediate position 320 via the stop 330 and/or the détente332, which may block the sleeve 250 from engaging the sun gear 232unless fluid is provided to the extension cavity 260 to drive thedétente 332 out of the corresponding groove 334 and/or block the sleeve250 from engaging the ring gear 236 unless fluid is provided to theretraction cavity 300 to drive the détente 332 out of the correspondinggroove 334. In some embodiments, the détente 332 may be utilized tomaintain the sleeve 250, and thus, the gear ratio, in any of the firstposition 252, the second position 290, or the third position 320relative to the drive shaft 76 without energizing the shift valves 214and/or without maintaining fluid pressure in the respective cavities orspaces 260, 300, 340, for example.

It should be understood that the shift valves 214 may be controlled by acontroller (e.g., electronic controller having a processor and amemory), such as the controller 136. As discussed above, the controller136 may be configured to receive an input (e.g., an operator input viathe user interface 142 of the controller 136 or a control signal) andmay respond to the input to open and/or to close the shift valves 214 toadjust the position of the sleeve 250, and thereby adjust the gear ratioof the transmission 64. Thus, in the illustrated embodiment, thetransmission 64 may shift gears without use of a clutch and/or a brake,for example. Furthermore, the various fluid passageways (e.g., the firstpassageway 262, the second passageway 304, and the stop passageway 338)are shown in a simplified form and/or certain fluid passageways areomitted from some of the figures to facilitate discussion. It should beunderstood that these passageways 262, 304, 338, as well as variouslubricant passageways, may generally extend from a fluid source, throughthe transmission housing 65, through the rotary union 264, and/orthrough the drive shaft 76 to respective cavities (e.g., the extensioncavity 260, the retraction cavity 300, the stop space 340). Each of thevarious passageways 262, 304, 338, as well as various lubricantpassageways, may be distributed circumferentially and/or axially (e.g.,positioned at discrete locations) about the transmission 64 (e.g., thetransmission housing 65, the rotary union 264, the drive shaft 76) tofacilitate fluid flow to the respective cavities.

FIG. 20 is a perspective view of a portion of the sleeve 250 that may beutilized in the transmission 64. As shown, a splined surface 348 (e.g.,external splined surface having one or more male and female splines orteeth or grooves) is formed about the radially-outer surface 247 of thesleeve 250 to engage the sun gear 232 and the ring gear 236 to shiftgears. The sleeve 250 also includes the radially-outwardly extendingprotrusion 276 that may enable the sensor 145 to monitor the position ofthe sleeve 250 within the transmission housing 65.

FIG. 21 is a cross-sectional perspective view of a portion of thetransmission 64, including the sleeve 250, the support sleeve 256, thedrive shaft 76, and the rotary union 264. As shown, a splined surface350 (e.g., internal splined surface having one or more male and femalesplines or teeth or grooves) is formed along the radially-inner surface249 of the sleeve 250 to engage a corresponding splined surface 352(e.g., external splined surface having one or more male and femalesplines or teeth or grooves) of the outer wall 257 of the drive shaft 76at the splined interface 251. The splined interface 251 enables thesleeve 250 to drive rotation of the drive shaft 76 and enables thesleeve 250 to move axially relative to the drive shaft 76. As shown, thedrive shaft 76 includes a lubricant passageway 354 to enable a flow offluid (e.g., lubricant or oil) to the cavity 221 of the drive shaft 76that is configured to surround the motor shaft 220 and/or to supportbearings (e.g., the first bearing 240 and the second bearing 242)positioned between the motor shaft 220 and the drive shaft 76. As shown,in some embodiments, the lubricant passageway 354 may direct the flow offluid to an interface 356 (e.g., annular space or annular contactingsurfaces) between the radially-inner surface 249 of the sleeve 250 andthe outer wall 257 of the drive shaft 76 to facilitate axial movement ofthe sleeve 250 relative to the drive shaft 76. In some embodiments, thelubricant passageway 354 may extend through the rotary union 264 (e.g.,the first and second components 266, 268) to enable the flow of fluidfrom a lubricant source (e.g., storage tank) to the lubricant passageway354, and the flow of fluid may be controlled by one of the shift valves214, in some embodiments.

As noted above, the components of the drawworks system 22 may have anyof a variety of configurations. For example, FIG. 22 is across-sectional side view of an embodiment of a portion of thetransmission 64 having a double-walled wear sleeve 350 (e.g., annularwear sleeve or thrust bearing) supporting an adjustable stop 352 (e.g.,annular stop or sleeve). The double-walled wear sleeve 350 and the stop352 may generally operate in a similar manner as the wear sleeve 336 andthe stop 330 discussed above with respect to FIG. 19, and the variousother features of the transmission 64 illustrated in FIG. 22 maygenerally operate in a similar manner as discussed above with respect toFIGS. 1-21 (e.g., the sleeve 250 may be driven to move between the firstposition 252 and the second position 290 to shift gears).

As shown, the double-walled wear sleeve 350 includes a radially-innerwall 351 (e.g., annular wall) and a radially-outer wall 355 (e.g.,annular wall) that define an annular space 353 configured to receiveand/or to support the stop 352. As shown, the stop 352 includes a firstend 357 configured to contact the sleeve 250 (e.g., the protrusion 276of the sleeve 250) and a second end 359 that is positioned within theannular space 355. In FIG. 22, the sleeve 250 is the third position 320in which the sleeve 250 is positioned between the first position 252 andthe second position 290 along the axial axis 40 and does not engage thegearset 230, and thus, the transmission 64 is in neutral, such thatrotation of the motor shaft 220 is not transferred to the drive shaft76. At least a portion of the double-walled wear sleeve 350 ispositioned between the stop 352 and the sleeve 250 along the radial axis42 to facilitate relative axial movement between the stop 352 and thesleeve 250, and the stop 352 is configured to limit and/or to blockmovement of the sleeve 250 along the axial axis 40. As shown, thedétente 332 is provided about the radially-inner surface 249 of thesleeve 250 and is configured to engage the groove 334 in theradially-outer surface 257 of the drive shaft 76. Together, the stop 352and the détente 332 may support the sleeve 250 in the intermediateposition 320 without energizing the shift valve 214 that provides thefluid to the retraction chamber 300.

In operation, to shift from the first position 252 to the intermediateposition 320, the respective shift valve 214 may be controlled toprovide fluid to the retraction chamber 300 via the second passageway304, thereby driving the sleeve 250 axially relative to the drive shaft76 in a first direction, as shown by arrow 354. At the same time, arespective shift valve 214, or other suitable valve, may be controlledto provide a flow of fluid through the stop passageway 338 to a stopspace 356 (e.g., annular space) to drive the stop 352 axially in asecond direction, opposite the first direction, as shown by arrow 358.The stop 352 may block the sleeve 250 from moving axially to the secondposition 290 and may block the sleeve 250 from engaging the ring gear236. In some embodiments, the fluid pressure within the retractioncavity 330 and/or the stop space 356 may be removed, and the sleeve 250may remain in the intermediate position 320 via the stop 352 and/or thedétente 332, which may block the sleeve 250 from engaging the sun gear232 unless fluid is provided to the extension cavity 260 to drive thedétente 332 out of the corresponding groove 334 and/or block the sleeve250 from engaging the ring gear 236 unless fluid is provided to theretraction cavity 300 to drive the détente 332 out of the correspondinggroove 334.

The motor assembly 52 illustrated in FIGS. 13-22 may facilitate themethod 150 of FIG. 12. For example, multiple motors 62 of the drawworkssystem 22 may be operated at a designated power and with respectivesleeves 250 of the respective transmissions 64 in the first position 252to provide a first gear ratio (e.g., 1:1 gear ratio) to drive rotationof the drum 54 via the gearbox 56 and to move a load at a first speed.As noted above, to achieve the first position 252, fluid may be providedto the extension cavity 260 to drive the sleeve 250 axially relative tothe drive shaft 76 to engage the sun gear 232 of the gearset 230.

After application of the brake 58 to block rotation of the drum 54, afirst transmission 64 coupled to a first motor 62 (e.g., a failed motor)may be switched to a neutral position by controlling a respective valve214 to provide a fluid to the retraction chamber 300 to drive the sleeve250 axially away from the sun gear 232 and also controlling a respectivevalve 214 to provide a fluid to drive the stop 330 in the oppositedirection along the axial axis 40 to limit movement of the sleeve 250and to block the sleeve 250 from engaging the ring gear 236.

In operation, a second transmission 64 coupled to a second motor 62(e.g., an intact motor) may be switched from the first gear ratio to asecond gear ratio (e.g., 2:1 gear ratio) by controlling a respectivevalve 214 to provide a fluid to the retraction chamber 300 to drive thesleeve 250 axially away from the sun gear 232 until the sleeve 250engages the ring gear 236. The brake 58 may then be returned to thenon-braked position to enable rotation of the drum 154, and the secondmotor 62 that is coupled to the second transmission 64 that is set atthe second gear ratio may be operated at the designated power to movethe load (e.g., the load at approximately half of the first speed). Sucha configuration may reduce downtime, increase the efficiency of certaindrilling operations (e.g., by enabling completion of certain drillingoperations), and/or may enable delay of repair to the first motor 62until a more convenient time, for example.

While the disclosure may be susceptible to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and have been described in detail herein.However, it should be understood that the disclosure is not intended tobe limited to the particular forms disclosed. Rather, the disclosure isto cover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the disclosure as defined by the followingappended claims. Furthermore, any of the features and components ofFIGS. 1-22 may be utilized together and/or combined in any suitablemanner.

The techniques presented and claimed herein are referenced and appliedto material objects and concrete examples of a practical nature thatdemonstrably improve the present technical field and, as such, are notabstract, intangible or purely theoretical. Further, if any claimsappended to the end of this specification contain one or more elementsdesignated as “means for [perform]ing [a function] . . . ” or “step for[perform]ing [a function] . . . ”, it is intended that such elements areto be interpreted under 35 U.S.C. 112(f). However, for any claimscontaining elements designated in any other manner, it is intended thatsuch elements are not to be interpreted under 35 U.S.C. 112(f).

The invention claimed is:
 1. A drawworks system for a mineral extractionsystem, comprising: a drum mounted on a drum shaft and configured tosupport a cable; a gearbox assembly, comprising: a gearbox housing; agearbox supported within the gearbox housing and comprising a gearboxinput shaft and a gearbox output shaft, wherein the gearbox input shaftis configured to be coupled to at least one motor and the gearbox outputshaft is coupled to the drum shaft to drive rotation of the drum shaftand the drum; and a brake coupled to a wall of the gearbox housing viaone or more fasteners and coupled to the drum shaft to block rotation ofthe drum shaft and the drum, wherein the drum shaft extends through thegearbox output shaft and into the brake, and wherein the gearbox and thebrake are positioned on one side of the drum along an axial axis of thedrawworks system.
 2. The drawworks system of claim 1, wherein thegearbox output shaft, the drum shaft, and the brake have a commonrotational axis.
 3. The drawworks system of claim 1, comprising the atleast one motor, wherein the at least one motor is positioned rearwardof the drum along a lateral axis of the system and a first rotationalaxis of an output shaft of the motor is parallel to a second rotationalaxis of the drum shaft.
 4. The drawworks system of claim 1, wherein thebrake comprises a pneumatic multi-disc brake.
 5. The drawworks system ofclaim 4, wherein the brake comprises a fail-safe brake.
 6. The drawworkssystem of claim 1, comprising two motors.
 7. The drawworks system ofclaim 6, wherein each of the two motors is coupled to a respectivemulti-speed transmission.
 8. A drawworks system for a mineral extractionsystem, comprising: a drum mounted on a drum shaft and configured tosupport a cable; a motor assembly configured to drive rotation of thedrum shaft, comprising: a first motor and a first transmissionconfigured to adjust a first power output of the first motor; and asecond motor and a second transmission configured to adjust a secondpower output of the second motor; and a gearbox assembly comprising agearbox supported within a gearbox housing and a brake disposed adjacentthe gearbox, wherein the gearbox housing is coupled to a skid, and thebrake is coupled to a wall of the gearbox housing via one or morefasteners and supported by the gearbox housing such that the brake issuspended above the skid.
 9. The drawworks system of claim 8, whereinthe gearbox comprises a gearbox input shaft coupled to respective driveshafts of the first motor and the second motor and a gearbox outputshaft coupled to the drum shaft, the brake is coupled to the drum shaftto block rotation of the drum shaft and the drum, and the gearbox ispositioned between the drum and the brake along an axial axis of thedrawworks system.
 10. The drawworks system of claim 8, wherein the firstmotor and the second motor each comprise an electric motor.
 11. Thedrawworks system of claim 8, wherein the first transmission and thesecond transmission each comprise a multi-speed planetary transmission.12. The drawworks system of claim 11, wherein the first transmission andthe second transmission each comprise a multi-speed transmissionconfigured to operate at a plurality of gear ratios, and a neutral gear.13. The drawworks system of claim 8, wherein the motor assembly ispositioned rearward of the drum along a lateral axis of the drawworkssystem.
 14. The drawworks system of claim 8, wherein the first motor andthe second motor have a common rotational axis that is parallel to arotational axis of the drum shaft.
 15. The drawworks system of claim 1,comprising a skid coupled to the gearbox housing, wherein the gearboxhousing is configured to support the brake to suspend the brake abovethe skid.
 16. The drawworks system of claim 1, wherein the drum shaft isa single piece component.